1. Field of the Invention
The present invention relates to an arrangement for clearing automobile windows and more particularly to a simple and complete arrangement for wiping, washing and defogging, especially the rear window mounted on a liftgate.
2. Description of the Prior Art
A method is known of wiping and washing the rear window of an automobile with a wiper motor-reducer assembly and a pump actuated by a momentary or permanent action switch located on the dash. French patent application No. 75/15 319 in the name of the present applicant actually describes a wiper motor-reducer controlled by momentary commands, associated with a means of prolonging the operation of the wiper until it reaches its rest position by the short-circuiting of the motor armature by means of a reverser controlled by the reducer output.
This simple control, nevertheless, requires the installation of three wires, the difficulty consisting in passing the wires from the front to the rear of the vehicle, then ensuring electrical continuity going from the body to the liftgate carrying the wiper-washer assembly.
A known solution is to connect the two wires supplying power to the ends of two current-carrying liftgate equilibrators.
It was necessary, then, to develop a wiper-washer arrangement able to operate entirely from two power leads in order to benefit from the connection through the liftgate equilibrators.
A modification of the object of the above mentioned application No. 75/15 319 eliminates one control wire, thanks to the introduction of a supplementary resupply diode or by replacing the reverser for prolonged operation with a more costly fast-break model, but it must be pointed out that only the wiper is concerned here.
It is known on the other hand how to supply, with just two wires, the system for defogging the rear window by electrical heating, but this solution again is incomplete.
Finally, there are sophisticated arrangements permitting two-wire control of the wiper and the defogger, but at the cost of a complex electronic circuit involving several relays, at least one of which is a delay relay, as well as other electronic components.